As the trailer hints, the docu is unflinching and uses previously unseen archival footage, demo recordings, rare performances, audio archives and interviews with friends and family who were there for Houston's ups and downs.

Houston's half-brother, ex-NBA basketball player Gary Garland, alleges that he and Houston were sexually abused by Warwick, who died in 2008, when he was aged between seven and nine. But in 2012, Houston died in a bathtub after struggling for years with substance abuse.

Whitney's focus on fizzy pop hits like "I Wanna Dance with Somebody" alienated her from many African-Americans - she was notoriously booed at the Soul Train Awards in the late 1980s. The filmmaker also revealed that he talked to Whitney's ex-husband, Bobby Brown.

Whitney Houston's legend status and star power were obvious; it was something everyone knew.

In this April 25, 2010 file photo, singer Whitney Houston performs at the o2 in London as part of her European tour.

Dee Dee Warwick in 1965. And she told me Whitney's point of view on this, and what Whitney had told her in detail, and how important she felt it was for understanding Whitney, but how scared everyone was to talk about it. Not necessarily in the public, but I don't think that was a secret within the music industry.

Macdonald continued: 'She seemed kind of asexual in a odd way. Dee Dee got her start singing in church and eventually started a gospel trio with Dionne and Cissy. And she said to me, "I just don't understand what happened, she was the most lovely girl, '".

Her presence is still very much felt and this documentary seems like the flawless, or as close to ideal, representation of her truth.